MAC reset and reconfiguration

ABSTRACT

A method and apparatus for reconfiguring a medium access control (MAC) entity in a wireless transmit receive unit (WTRU). The method and apparatus includes the WTRU transmitting a MAC reconfiguration request, the WTRU receiving a MAC reconfiguration command including new MAC parameter values and the WTRU reconfiguring a MAC entity based on the new MAC parameter values in the MAC reconfiguration command.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/087,443 filed on Aug. 8, 2008, which is incorporated by reference asif fully set forth.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

Goals of the 3rd Generation Partnership Project (3GPP) Long TermEvolution (LTE) program include developing new technology, newarchitecture and new methods for new LTE settings and configurations inorder to provide improved spectral efficiency, reduced latency, betterutilizing the radio resource to bring faster user experiences and richerapplications and services with less cost.

FIG. 1 shows an overview of an Evolved Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access Network(E-UTRAN) 100 in accordance with the prior art. As shown in FIG. 1,E-UTRAN 100 includes three eNodeBs (eNBs) 102, however, any number ofeNBs may be included in E-UTRAN 100. The eNBs 102 are interconnected byan X2 interface 108. The eNBs 102 are also connected by an S1 interface106 to the Evolved Packet Core (EPC) 104 that includes a MobilityManagement Entity (MME) 112 and a Serving Gateway (S-GW) 110.

FIG. 2 shows an LTE user-plane protocol stack 200 in accordance with theprior art. The protocol stack 200 is located in a wireless transmitreceive unit (WTRU) 210 and includes the packet data control protocol(PDCP) 202, the radio link control (RLC) 204, the medium access control(MAC) 206 and the physical layer (PHY) 208. The protocol stack 200 mayalso reside in an eNB (not shown).

FIG. 3 shows an LTE control plane protocol stack 300 of the WTRU 210 ofFIG. 2. The control plane protocol stack 300 includes the non-accessstratum (NAS) 302 and a radio resource control (RRC) 304. Also includedare the PDCP 306, RLC 308 and MAC 310, which together form the layer 2sublayer 312.

The MAC entity may be reset or reconfigured as required. Areconfiguration occurs when one or more of the MAC entity's parameters,such as random access channel (RACH) parameters, are modified. A MACreset procedure my be performed at handover, cell-reselection, radioresource control (RRC) connection re-establishment and upon the WTRUmoving from RRC connected state to RRC idle state.

The parameters for a MAC entity may be reconfigured by the upper layers.When a RACH parameter is reconfigured by an upper layer, the WTRU maystart using new RACH parameters the next time the random accessprocedure is initiated. This may include if an available set of physicalrandom access channel (PRACH) resources for the transmission of therandom access preamble and their corresponding radio access-radionetwork temporary identifiers (RA-RNTIs) are modified, for example. Thismay also include modifying groups of random access preambles and a setof available random access preambles in each group. Other parameters maybe modified, such as the thresholds required for selecting a group ofrandom access preambles, the parameters required to derive thetransmission time interval (TTI) window, the power-ramping factor, themaximum preamble transmission power, the initial preamble transmissionpower, the maximum number of message hybrid automatic retransmissionrequest (HARQ) transmissions, the preamble transmission counter, and thebackoff parameter, for example. For other modified parameters, the WTRUmay start using the reconfigured value of the parameter immediately.

FIG. 4 shows a method of resetting a MAC entity 400 in accordance withthe prior art. In step 402, the WTRU flushes all hybrid automatic repeatrequest (HARQ) buffers. At step 404, the WTRU initializes a counter,CURRENT_TX_NB, which counts the number of transmissions that have takenplace for the MAC protocol data unit (PDU) currently in the buffer. TheWTRU sets the counter to zero for all HARQ processes. At step 406, thedisassembly and demultiplexing entity are flushed. At step 408, the WTRUwill detect if a random access procedure is ongoing. If so, at step 410,the WTRU will abort the ongoing random access procedure. At step 412,the WTRU will flush a message buffer, and at step 414, it willinitialize the preamble transmission counter to zero. At step 416, theWTRU may consider the contention resolution timer to be expired anddiscard the cell radio network temporary identifier (C-RNTI). Thecontention resolution timer specifies the number of consecutive physicaldownlink control channel (PDCCH) subframes that the WTRU monitors on thePDCCH after the uplink message containing the C-RNTI MAC control elementor the uplink message associated with WTRU contention resolutionidentity submitted from a higher layer is transmitted. At step 418, theWTRU may adjust a number of timers, such as the time alignment timer,the on-duration timer, the DRX inactivity timer, the DRX retransmissiontimer, the DRX short cycle timer, the periodic buffer status report(BSR) timer and the power head room (PHR) timer, for example.

SUMMARY

A method and apparatus are disclosed for resetting and reconfiguring amedium access control (MAC) entity in a wireless transmit receive unit(WTRU). This may include a transmitter in a WTRU transmitting a MACreset or reconfiguration request. A receiver in a WTRU may receive a MACreset or reconfiguration command that includes new MAC parameter values.The WTRU may reconfigure the MAC entity based on the new MAC parametervalues taken from the MAC reconfiguration command or reset all the MACparameters.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1 shows an overview of an Evolved Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access Network(E-UTRAN) in accordance with the prior art;

FIG. 2 shows an LTE user-plane protocol stack in accordance with theprior art;

FIG. 3 shows an LTE control plane protocol stack of the WTRU of FIG. 2.

FIG. 4 shows a method of resetting a MAC entity in accordance with theprior art;

FIG. 5 shows a wireless communication system including a plurality ofWTRUs and an e Node B (eNB); and

FIG. 6 is a functional block diagram of the WTRU and the eNB of thewireless communication system of FIG. 5;

FIG. 7 is a signal diagram of a method for MAC reconfiguration inaccordance with an embodiment;

FIG. 8 shows a method of MAC reconfiguration in accordance with anembodiment;

FIG. 9 shows a method of reconfiguring RACH or DRX parameters inaccordance with an embodiment;

FIG. 10 shows a method of reconfiguring SPS parameters in accordancewith an embodiment;

FIG. 11 shows a method for a MAC reset in accordance with an embodiment;

FIG. 12 shows a method for a MAC reset in accordance with anotherembodiment;

FIG. 13 shows a method resetting RACH parameters in accordance with anembodiment;

FIG. 14 shows a method for resetting DRX parameters in accordance withan embodiment;

FIG. 15 shows a method for resetting SPS parameters in accordance withan embodiment; and

FIG. 16 shows a method for resetting HARQ parameters in accordance withan embodiment.

DETAILED DESCRIPTION

When referred to hereafter, the terminology “wireless transmit/receiveunit (WTRU)” includes but is not limited to a user equipment (UE), amobile station, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a computer, or any othertype of user device capable of operating in a wireless environment. Whenreferred to hereafter, the terminology “base station” includes but isnot limited to a Node-B, a site controller, an access point (AP), or anyother type of interfacing device capable of operating in a wirelessenvironment. The method disclosed herein may be performed in anysequence, and are not limited to the sequence shown in any particularembodiment.

FIG. 5 shows a wireless communication system 500 including a pluralityof WTRUs 510 and an e Node B (eNB) 520. As shown in FIG. 5, the WTRUs510 are in communication with the eNB 520. Although three WTRUs 510 andone eNB 520 are shown in FIG. 5, it should be noted that any combinationof wireless and wired devices may be included in the wirelesscommunication system 500.

FIG. 6 is a functional block diagram 600 of a WTRU 510 and the eNB 520of the wireless communication system 500 of FIG. 5. As shown in FIG. 5,the WTRU 510 is in communication with the eNB 520. The WTRU 510 isconfigured with a PHY entity, MAC entity, RRC entity and an RLC entity.The WTRU 510 is further configured to receive and transmit messages toand from, respectively, each of the entities.

In addition to the components that may be found in a typical WTRU, theWTRU 510 includes a processor 615, a receiver 616, a transmitter 617,and an antenna 618. The WTRU 510 may also include a user interface 618,which may include, but is not limited to, an LCD or LED screen, a touchscreen, a keyboard, a stylus, or any other typical input/output device.The WTRU 510 may also include memory 619, both volatile and non-volatileas well as interfaces 620 to other WTRU's, such as USB ports, serialports and the like. The receiver 616 and the transmitter 617 are incommunication with the processor 615. The antenna 618 is incommunication with both the receiver 616 and the transmitter 617 tofacilitate the transmission and reception of wireless data.

In addition to the components that may be found in a typical eNB, theeNB 520 includes a processor 625, a receiver 626, a transmitter 627, andan antenna 628. The receiver 626 and the transmitter 627 are incommunication with the processor 625. The antenna 628 is incommunication with both the receiver 626 and the transmitter 627 tofacilitate the transmission and reception of wireless data. The eNB 520is configured with a PHY entity, a MAC entity and an RRC entity.

MAC Reconfiguration

An RRC entity may reconfigure a MAC entity. To begin the process, theMAC entity may send a signal to the RRC entity to request, or trigger,the reconfiguration. Any one of the events listed below may cause theMAC to request that the RRC send a reconfiguration command to the MAC:

-   -   a. a predetermined threshold number of random access channel        (RACH) retries has been reached;    -   b. the reserved dedicated RACH preambles expire;    -   c. SPS transitions from the talk-spurt period to the silent        period;    -   d. SPS transitions from the silent period to talk-spurt period;    -   e. the discontinuous reception (DRX) function loses        synchronization between the WTRU and the eNB;    -   f. a failure of the transmission time interval (TTI) bundling        retransmissions;    -   g. the number of retransmissions of data exceeds the maximum        number of retransmissions allowed; and    -   h. one or more of the WTRU's buffers is full or about to become        full (as determined using one or more thresholds), including,        but not limited to the overall buffer, a per-logical-channel        buffer; a MAC buffer or an upper-layer buffer.

The MAC reconfiguration procedure may be initiated by the WTRU bytransmitting a reconfiguration request to the eNB, for example. The WTRUmay transmit the MAC reconfiguration request to the eNB through an RRCor a MAC communication element (CE). The reconfiguration request mayinclude a cause value that indicates the reason for the MACreconfiguration request, identification of the MAC entity to bereconfigured, an indication of the functions to be reconfigured and anindication of the parameters to be reconfigured

Alternatively, the reconfiguration procedure may be initiated by the eNBand signaled to the WTRU. The eNB may transmit an RRCmessage/information element (IE) to the WTRU. In response, the WTRU mayperform MAC reconfiguration based on the information indicated in theRRC message.

FIG. 7 is a signal diagram of a method for MAC reconfiguration 700 inaccordance with an embodiment. As shown in FIG. 7, a WTRU 702 and an eNB704 may send and receive MAC CEs (706, 708, 710) to reconfigure the MACentity. The MAC CEs (706, 708, 710) may be used when MAC reconfigurationis requested from the MAC entity of the WTRU 702. The MAC CEs (706, 708,710) include a MAC CE to request MAC reconfiguration 706, a MAC CE toacknowledge reception of MAC reconfiguration 708, and a MAC CE toconfirm the completion of MAC reconfiguration process 710. The MAC CEmay also contain the reconfiguration parameters.

FIG. 8 shows a method of MAC reconfiguration 800 in accordance with anembodiment. At step 802, the MAC entity in a WTRU receives an RRC signalor a MAC CE indicating that the MAC should reconfigure its parameters.At step 804, the MAC entity reconfigures MAC state variables to theirinitial values, default values, or values that are included in the MACCE or RRC signal. At step 806 the MAC entity reconfigures MAC parametersto values that are included in the MAC CE or RRC signal. At step 808 theWTRU starts, stops or restarts timers associated with the reconfiguredfunctions of the MAC entity, such as the on-duration timer andinactivity timer associated with reconfiguring a DRX cycle, for example.At step 810, the WTRU stops and/or restarts counters associated with thereconfigured functions of the MAC entity, such as the number of retriesof RACH preambles, for example. At step 812, the WTRU confirmscompletion of the reconfiguration procedures to the eNB and at step 814,the WTRU indicates completion of reconfiguration to the upper layers.

The new values of the parameters of a reconfigured MAC entity may not beapplied immediately after the MAC entity receives the new values. TheMAC reconfiguration may be synchronized with RRC or MAC CE messaging.The RRC or MAC CE messaging may include an explicit or implicitindication of the time of activation of the new parameter values.Alternatively, the activation may be based on a transmission timeinterval (TTI) or a system frame number (SFN). For example, the RRC orMAC CE messaging may be synchronized with the new value activation whichmay be aligned with a SFN or a number of TTIs relative to the last TTIin which the RRC or MAC CE message was transmitted or received.

FIG. 9 shows a method of reconfiguring RACH or DRX parameters 900 inaccordance with an embodiment. At step 902 the WTRU receives areconfiguration message for RACH or DRX parameters. At step 904, theWTRU reads the reconfigured RACH or DRX parameters from thereconfiguration message and determines if the reconfigured parametersare modified values. At step 906, the WTRU determines if the requestedparameters are configured to new values. If the requested parameters arenot configured to new values, at step 908 the WTRU resets the requestedparameters to initial or default values. Otherwise, at step 910, theWTRU replaces the old parameter values with the new parameter values.

If the new parameter values are for the RACH, the values are applied thenext time a RACH procedure is initiated. The WTRU may also be configuredto apply new parameters for the dedicated RACH procedure when the WTRUand the eNode-B are synchronized.

For new DRX timer values, the WTRU may apply the new parameters in thenext TTI or it may wait until the old timer expires and apply the newtimer value when the timer is initiated.

FIG. 10 shows a method of reconfiguring SPS parameters 1000 inaccordance with an embodiment. At step 1002, the WTRU receivesreconfiguration message for SPS. At step 1004, the WTRU detects if thereconfiguration is for a transition from a talk-spurt state to a silentstate, or from silent state to talk-spurt state. If the transition isfrom talk-spurt to silent state, at step 1006, the WTRU deallocates theradio resource configured for the talk-spurt state, and, at step 1008,the WTRU configures the radio resource or parameters used for a silentperiod.

If, at step 1004, the WTRU detects the reconfiguration is fromtalk-spurt state to silent state, at step 1010 the WTRU sets up theradio resource. At step 1012 the WTRU configures the parameters for thetalk-spurt state.

The deallocation for the old configuration and the configuration of thenew parameter values may be performed in next immediate TTI.Alternatively the timing of the activation of the values for thereconfigured parameters may be based on an activation time conveyed inthe reconfiguration message.

If a WTRU detects the reconfiguration is for the parameters of existingtalk-spurt period or if the reconfiguration is for the extension ofcurrent talk-spurt period, then the WTRU may continue the persistenttransmission after the expiration of the current configuration.Alternatively, if parameters are reconfigured for an extension ofcurrent talk-spurt period, the new parameters should be used in theextended persistent transmission period.

When a WTRU receives a reconfiguration message for a HARQ process, thenthe WTRU may flush the HARQ buffer for the configured HARQ process.Next, it may initialize the CURRENT_TX_NB to zero for configured HARQprocess. And finally the WTRU may apply the reconfigured values in thenext TTI or based on the activation time indicated in thereconfiguration message.

MAC Reset

For a MAC reset, the MAC entity may indicate to the RRC entity that aMAC reset is required. The reasons for a MAC reset may be different thanthe reasons for a MAC reconfiguration. A MAC reset may be triggered by ahandover, cell-reselection or an RRC state transition from connectedmode to idle mode, for example. Other triggers for a MAC reset mayinclude:

-   -   a) reaching a predetermined number of RACH retries;    -   b) expiry of reserved dedicated RACH preambles;    -   c) the DRX function losing synchronization between the WTRU and        the eNB;    -   d) a number of retransmissions of data exceeding the maximum        number of retransmissions allowed;    -   e) a radio link failure;    -   f) a handover command is transmitted indicating a MAC reset;    -   g) a measurement indicates that a neighboring cell provides        better signal quality than the source cell and the WTRU decides        to transmit handover request;    -   h) a measurement indicates that a neighbor cell provides better        signal quality than the source cell and WTRU decides to perform        cell reselection;    -   i) a number of retransmissions of control elements (CE's)        exceeds a maximum number of retransmissions allowed; and/or    -   j) token buckets (used for PBR or Aggregate-MBR) exhibit        problems, such as, one or more token buckets remain less than or        equal to zero (0) for more than a specified time/threshold        and/or one or more of the WTRU's buffers is full or about to        become full, for example.        Other events may also trigger a MAC reset.

FIG. 11 shows a method for a MAC reset 1100 in accordance with anembodiment. At step 1102, the MAC entity transmits a MAC reset requestto the RRC. At step 1104 a timer (Tmac_reset) is started. The timer maybe specific to each MAC entity. At step 1106 the WTRU may wait for thetimer to expire or wait for an indication from the RRC entity. Theindication from the RRC entity may be an acknowledgement of the resetrequest and/or confirmation of the reset procedures being initiated bythe RRC. At step 1108, the WTRU suspends transmission of any MAC PDUsfrom the entity being reset. At step 1110, the WTRU flushes the bufferof any MAC SDUs sent before the reset. At step 1112, the WTRU suspendsthe multiplexing and assembly of MAC SDUs. At step 1114, the WTRUsuspends reception of any MAC PDUs by the MAC entity being reset. Thiscan occur by discarding any received MAC PDUs. At step 1116 a counter(Cmac_reset) is incremented or decremented. The counter keeps a count ofthe number of reset requests. This counter may be specific to each MACentity. At step 1118 the WTRU resets the parameters of the MAC entity totheir initial configured values.

FIG. 12 shows a method for a MAC reset in accordance with anotherembodiment. In FIG. 12, at step 1202, a receiving MAC entity receives acommand from a receiving RRC entity to reset the MAC entity. At step1204, the WTRU resets at least one MAC state variable to itsinitial/default value or to the value configured in the reset request.At step 1206, the WTRU resets configurable parameters to theirconfigured values or to a new value received in the reset request. Atstep 1208, timers associated with the MAC entity are stopped and/orrestarted as required. At step 1210, A WTRU stops disassembly anddemultiplexing. At step 1212, the WTRU discards HARQ PDUs from the HARQtransmit buffer in the transmitting side of the MAC entity and notifiesthe upper layers of the discarded corresponding MAC SDUs. At step 1214the WTRU discards MAC SDUs from the SDU transmit buffer in thetransmitting side of the MAC entity and notifies the upper layers of thediscarded SDUs.

After receiving the notification, an upper layer, such as the RLCentity, for example, may resubmit SDUs for transmission to the MACentity below it, following the completion of the MAC reset. In thetransmitting side of the MAC entity, MAC SDUs are not discarded from theSDU transmit buffer of the MAC entity. The upper layers are notifiedabout all SDUs whose reception has not been acknowledged by the peer MACentity, such as through a HARQ ACK, for example. After receivingnotification, the upper layer may resubmit those SDUs to the MAC entityfor transmission. The MAC entity may confirm completion of the resetprocedures to the RRC and indicate the completion of reset to upperlayers. These actions may also be performed immediately after the MACprovides an indication to the RRC.

The eNB may include a C-RNTI in a MAC reset message. After a radio linkfailure, the WTRU may receive a MAC reset message and detect that theC-RNTI is the same as the original source cell. The WTRU may thendetermine that it is communicating with the same cell as before theradio link failure and does not need to override the previouslyconfigured parameters. However, if the WTRU detects a different C-RNTI,then the WTRU may determine that it is communicating with a differentcell and the original parameters should be reset with newly configuredparameters.

The timing of the MAC reset may be synchronized with RRC messaging. TheRRC messaging may include an explicit or implicit indication of thetiming of the reset or the activation of reset. Alternatively, thetiming of the reset may be accomplished on a TTI or SFN basis. Forexample, the synchronization between the RRC messaging and the MAC resetmay be aligned with the SFN or a number of TTI's relative to the lastTTI in which the RRC message was transmitted or received.

When an eNB resets a MAC entity in a WTRU, the MAC reset procedure mayinclude a reset of specific MAC functions, such as SPS, DRX or RACH, forexample. FIG. 13 shows a method for a dedicated RACH reset 1300 inaccordance with an embodiment. At step 1302 the WTRU aborts the ongoingdedicated RACH process. At step 1304 the WTRU forces the timer for thereserved dedicated RACH preamble to expire. At step 1306 the dedicatedpreamble transmission counter is initialized to zero. At step 1308 thereserved dedicated RACH preamble is flushed and replaced with a newpreamble. At step 1310 the timing alignment timer is treated as if it isexpired. At step 1312 the new parameters for the dedicated RACHprocedure are applied when the WTRU and the eNB are synchronized.

FIG. 14 shows a method for a DRX reset 1400 in accordance with anembodiment. At step 1402 the WTRU transmits the MAC reset indication toa higher layer. At step 1404 the WTRU stops transmitting SR/BSR to theeNB. At step 1406, the WTRU determines if the on-duration timer hasexpired. If so, at step 1408, the WTRU detects the MAC reset message. Atstep 1410 the WTRU determines if the on-duration timer value has beenreset to a new value. If so, at step 1412, the new value is applied. Ifnot, at step 1414, the old value is left unchanged. At step 1416, allnew values are applied at the start of the next on-duration.

At step 1406, if the on-duration timer has not expire before the WTRUreceives the MAC reset message, at step 1418 the WTRU detects the MACreset message. At step 1420 the WTRU determines if the on-duration timervalue has been reset to a new value. If so, at step 1422, the new valueis applied. If not, at step 1424, the old value is left unchanged. Atstep 1426, the new values for all parameters are applied immediately inthe current TTI or from the next TTI by considering the elapsedon-duration period.

At step 1428, the WTRU starts the DRX inactivity timer with either a newvalue or original value when it receives a PDCCH transmission, or needsto transmit SR. Alternatively it may restart the DRX inactivity timerfrom current TTI or next TTI if WTRU receives MAC reset message while itis running.

At step 1430, the WTRU stops the DRX retransmission timer if running. Ifa new value is reset then it will apply a new timer value when it isstarted in the future. Also, the WTRU may stop the DRX short cycle timerif running. If a new value is reset then it will apply a new timer valuewhen it is started in the future. Also, the WTRU will stop the DRX longcycle timer if it is running. If a new value is reset then the new timervalue is applied when it is started in the future. Finally, at step1432, the WTRU transmits a channel quality indicator (CQI)/SRS accordingthe new timing and active time duration.

FIG. 15 shows a method for SPS reset 1500 in accordance with anembodiment. At step 1502 the WTRU transmits a MAC reset indication to anupper layer and optionally stops current SPS transmission. At step 1504,the WTRU receives a MAC reset message for SPS. At step 1506 the WTRUreleases all of the reserved HARQ processes for SPS. At step 1508 theWTRU flushes the buffers of all the reserved HARQ processes. At step1510, the WTRU initializes the counter for retransmissions of allreserved HARQ processes. At step 1512 the WTRU resets all timers relatedto SPS. At step 1514 the WTRU resets the parameters for all reservedHARQ processes. At step 1516 the WTRU resets the TTI bundling parametersused for SPS, such as the number of TTIs used for bundling and RVvalues, for example. At step 1518 the WTRU configures SPS with new HARQIDs.

For uplink (UL) SPS after the WTRU transmits a MAC reset indication toan upper layer, the WTRU may suspend all UL SPS transmission and waitfor the reset message.

FIG. 16 shows a general HARQ process for MAC reset in accordance with anembodiment. At step 1602, the WTRU flushes HARQ buffers. At step 1604,the WTRU initializes all HARQ related parameters such as number ofretransmissions. At step 1606, the WTRU resets RV values. At step 1608the WTRU resets TTI bundling parameters.

Although features and elements are described above in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

What is claimed is:
 1. A method for reconfiguring a medium accesscontrol (MAC) entity in a wireless transmit receive unit (WTRU), themethod comprising: transmitting a MAC reconfiguration request; receivinga MAC reconfiguration command that includes updated MAC parametervalues, the updated MAC parameter values including one or more randomaccess channel (RACH) parameter values, the RACH parameter values beingapplied in response to an initiation of a RACH procedure; reconfiguringthe MAC entity based on the updated MAC parameter values in the MACreconfiguration command; receiving a message including a time to applythe updated MAC parameter values; and applying the updated MAC parametervalues based on the message.
 2. The method as in claim 1 wherein theupdated MAC parameter values further include hybrid automatedretransmission request (HARD) process parameters.
 3. The method as inclaim 1 wherein the updated MAC parameter values further includesemi-persistent scheduling (SPS) parameter values.
 4. The method as inclaim 1 wherein the updated MAC parameter values further includediscontinuous reception (DRX) parameter values.
 5. The method as inclaim 1 further comprising the WTRU reading the reconfiguration commandand determining modified parameter values.
 6. The method as in claim 1further comprising: adjusting a timer; adjusting a counter; andtransmitting a reconfiguration complete message.
 7. The method as inclaim 1 further comprising; applying new timer values based on a timerreinitialization; and applying new counter parameter values based on acounter reinitialization.
 8. The method as in claim 1 further comprisingapplying the updated MAC parameter values based on a system frame number(SFN).
 9. The method as in claim 1 further comprising applying theupdated MAC parameter values based on time transmission interval (TTI).10. A wireless transmit receive unit (WTRU) configured to reconfigure amedium access control (MAC) entity, the WTRU comprising: a transmitterconfigured to transmit a MAC reconfiguration request; a receiverconfigured to: receive a MAC reconfiguration command including updatedMAC parameter values, the updated MAC parameter values including one ormore random access channel (RACH) parameter values, the RACH parametervalues being applied in response to an initiation of a RACH procedure;and receive a message that includes a time to apply the updated MACparameter values; and a processor configured to reconfigure the MACentity based on the updated MAC parameter values in the MACreconfiguration command and configured to apply the updated MACparameter values based on the message.
 11. The WTRU as in claim 10wherein the updated MAC parameter values further include hybridautomated retransmission request (HARM) process parameters.
 12. The WTRUas in claim 10 wherein the updated MAC parameter values further includesemi-persistent scheduling (SPS) parameter values.
 13. The WTRU as inclaim 10 wherein the updated MAC parameter values further includediscontinuous reception (DRX) parameter values.
 14. The WTRU as in claim10 wherein the processor is further configured to read thereconfiguration command and determining modified parameter values. 15.The WTRU as in claim 10 wherein the processor is further configured toadjust a timer and adjust a counter, and the transmitter is furtherconfigured to transmit a reconfiguration complete message.
 16. The WTRUas in claim 10 wherein the processor is further configured to apply newtimer values based on a timer reinitialization and apply new counterparameter values based on a counter reinitialization.
 17. The WTRU as inclaim 10 wherein the processor is further configured to apply theupdated MAC parameter values based on a system frame number (SFN). 18.The WTRU as in claim 10 wherein the processor is further configured toapply the updated MAC parameter values based on time transmissioninterval (TTI).